A75 Trunk Road Asphalt Reinforcement

The A75 in Dumfries & Galloway is a vital transport route in southwest Scotland, connecting the A74/M74 at Gretna to the key ferry port at Stranraer. As a major freight corridor, the road carries thousands of heavy goods vehicles (HGVs), placing significant stress on the pavement structure.

Despite improvement works carried out in the late 1980s, sections of the A75 continued to experience long-term settlement issues. A critical failure occurred on a stretch east of Newton Stewart, where the road had been constructed over a poorly drained clay subgrade. This weak foundation, combined with constant heavy traffic loading, led to excessive pavement deflection and severe deterioration of the asphalt wearing course.

Previous maintenance and remedial works failed to resolve the issue, and continued monitoring confirmed ongoing structural failure. With both sides of the single carriageway affected, Dumfries & Galloway Combined Services Department required a durable, long-term pavement reinforcement solution. They engaged Maccaferri, specialists in road reinforcement systems, to provide technical expertise.

To restore structural integrity and extend pavement lifespan, a reinforced asphalt overlay solution was implemented using Maccaferri’s Road Mesh™, a high-performance double-twist steel wire mesh designed for asphalt pavement reinforcement.

The rehabilitation process involved planing off the existing damaged wearing course to expose the underlying layer. Road Mesh™ was then installed within the bituminous layers before applying a new asphalt base course and wearing course. This method integrates the mesh directly into the pavement structure, enhancing its mechanical performance.

Road Mesh™ works by absorbing tensile stresses and distributing traffic loads more evenly across the pavement. This reduces strain on weak subgrades, limits reflective cracking, and prevents further deformation, making it particularly effective for roads subject to heavy traffic and poor ground conditions.

The project was completed in 1999 by Dumfries & Galloway Council, with Barr as the main contractor. Since installation, the reinforced section of the A75 has demonstrated long-term performance, with no recurrence of the previous surface failures. This case highlights the effectiveness of steel mesh reinforcement in extending pavement life and reducing maintenance costs on heavily trafficked roads.